drm/amdgpu/jpeg: mmsch_v4_0_3 requires doorbell on 32 byte boundary

BASE: VCN0 unified (32 byte boundary)
BASE+4: MJPEG0
BASE+5: MJPEG1
BASE+6: MJPEG2
BASE+7: MJPEG3
BASE+12: MJPEG4
BASE+13: MJPEG5
BASE+14: MJPEG6
BASE+15: MJPEG7

Signed-off-by: Samir Dhume <samir.dhume@amd.com>
Acked-by: Leo Liu <leo.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>